The Latin term genitalia, sometimes anglicized as genitals and genital area, is used to describe the externally visible sex organs, known as primary genitalia or external genitalia: in males the penis.

The other, hidden sex organs are referred to as the secondary genitalia or internal genitalia. The most important of these are the gonads, a pair of sex organs, specifically the testes in the male . Gonads are the true sex organs, generating reproductive gametes containing inheritable DNA. They also produce most of the primary hormones that affect sexual development, and regulate other sexual organs and sexually differentiated behaviors.